You will remember that a Principle of Design acts on the Elements of Design to create meaning and impressions.
Progression, sometimes called “Gradation” means difference, change and interest, and relates closely to Repetition.
The change might be smooth, like an ombré, or a series of steps – like pixels. Progression might show the feeling of fast acceleration, or ponderous movement. It might be steady or jerky. It might be symmetrical or lopsided. Plus Progression may go in two directions like a bell curve.
In functional design, the pace of progression might relate to functionality – like a clock, designed specifically to maintain a steady pace of movement, through time.
Consider Ravel’s “Bolero” – a constant build of energy and complexity with the same few notes and beats.
Consider any kind of narrative, building to a climax and catharsis or resolution.
Calligraphy is made possible through gradations of Line. Progression of Size creates the impression of perspective, or discombobulates it. Progression is used to create the sensation of solidity – shading and shadows for 3D in flat artwork.
Photos of a sequence of events over time – the illustration of a work-in-progress, or a garden’s flowering, or a child’s growth – are a common use of Progression.
Here’s about 9 1/2 minutes of serenity with flowers blooming for your enjoyment.